1. Field of the Invention
The present invention relates to a method and apparatus for the separation of gaseous isotope compounds, especially of UF.sub.6, by means of selective excitation of the one isotope compound by electromagnetic radiation after adiabatic expansion of the gas.
2. Description of the Prior Art
Such methods have as their objective to raise the content of fissionable uranium isotope 235 in the starting material for the nuclear fuel manufacture from 0.7% (the natural isotope composition) to about 3% and to thereby create the condition for its use as nuclear fuel in light-water reactors. Many of the proposals made so far amount to bringing a uranium isotope or its compound as UF.sub.6 by laser excitation to a more highly excited, and therefore, higher-energy state and to enable it thereby to enter preferentially into a chemical reaction with a reaction partner and to separate the reaction products stemming therefrom from the original gas mixture by, for instance, physical means. It has been found to be particularly advantageous to cool the gaseous isotope mixture to be fed-in by adiabatic expansion to a low temperature, for instance, to 30.degree.-50.degree. K., since in this manner a clear separation of the spectra by the isotopy shift occurs, especially in the Q-branches of the UF.sub.6. This makes possible selective engagement of only the one isotope compound by means of a laser beam, the frequency of which is adjusted accordingly. For a further explanation of such an isotope separation method, reference is made to German published non-prosecuted patent application No. 24 47 762, corresponding U.S. patent application, Ser. No. 614,213 now abandoned.
In addition to these chemical reactions made possible by laser excitation, it is also possible to choose the expansion conditions so that condensation takes place in the gas jet, and to prevent the 235 UF.sub.6 molecules from condensing or from attaching themselves to condensing or already condensed particles by isotope-specific laser excitation. The large mass difference caused thereby between the particles produced in the original gas jet can then be utilized for the separation thereof, as is proposed, for instance, in German application No. 26 59 590, corresponding U.S. patent application Ser. No. 862,504 now abandoned.